1. Field of the Invention
The present invention relates to a changeable view angle type liquid crystal device which can select between wide view angle display and narrow view angle display, and a liquid crystal display apparatus using the same.
2. Description of the Related Art
Since a liquid crystal display device has a wide view angle, its display might be seen by someone other than the viewer, from a direction inclined from the front forward direction.
Hence, there has been proposed a liquid crystal display apparatus which limits the view angle of the liquid crystal display device by using a view angle limiting device, which is disposed on one surface of the liquid crystal display device, and whose area corresponding to the screen of the liquid crystal display device is divided into a plurality of regions to make the liquid crystal molecules in the respective regions aligned in different alignment states region by region (Unexamined Japanese Patent Application KOKAI Publication No. 2004-133334).
The view angle limiting device is structured such that its area corresponding to the screen of the liquid crystal display device is divided into a plurality of regions, so that in each region, the liquid crystal molecules of a liquid crystal layer, which is sealed between a pair of substrates, are aligned in an alignment state having a view angle in a direction inclined to one side from a normal line of the liquid crystal display device, and in an alignment state having a view angle in a direction inclined from the normal line to a reverse side to that side. The pair of substrates of the view angle limiting device have electrodes having a predetermined shape on their inner surfaces facing each other.
Such a liquid crystal display apparatus limits the view angle of an image displayed by the liquid crystal display device, by applying a voltage between the electrodes of the view angle limiting device to reduce the visibility from an oblique observing direction.
Specifically, when no voltage is applied between the electrodes of the view angle limiting device, i.e., when the view angle limiting device is in a non-display status, the display image of the liquid crystal display device can be seen at a wide view angle. Contrarily, when a voltage is applied between the electrodes of the view angle limiting device, the display image of the liquid crystal display device is hidden by display made by the respective regions of the view angle limiting device, that have a view angle in the direction inclined to one side, and display made by the respective regions that have a view angle in the direction inclined to the reverse side, if the display image of the liquid crystal display device is observed from a direction inclined to one side from the front forward direction, and from a direction inclined to the reverse side to that side. Therefore, the display image of the liquid crystal display device cannot be recognized from the direction inclined to one side and from the direction inclined to the reverse side, and the view angle of the display image is seemingly limited and becomes narrow.
However, the view angle limiting device is hard to manufacture, because a complex aligning process (rubbing on aligning films) for imparting different directivities to each region has to be applied to the inner surfaces of the pair of substrates, in order to align the liquid crystal molecules of the liquid crystal layer in different alignment states region by region.
Further, a changeable view angle type liquid crystal display apparatus having the above-described view angle limiting device has to use two liquid crystal devices, thus has a problem that the apparatus becomes thick and its structure becomes complicated.